acid-phosphatase and aluminum-fluoride

Protective role of diet supplements (Spirulina, tamarind fruit pulp and their combination) on a freshwater fish G. affinis exposed at sublethal concentration of fluoride (F-) (10 ppm), Al(+3) (3 ppm) and aluminum fluoride (AlF3) (35.4 ppm) in the microcosms (15 L sized) for 30-60 days in winter (90 days in summer) has been reported. Toxic effects of chemicals were manifested as higher fish mortality (4-50%) and acid (approximately -30%) and alkaline phosphatase (25-50%) contents, but reduction in RBC counts (5-55%) and protein content (approximately -29%) compared with controls. Alterations in values of these parameters were found maximum in aluminum exposed fish suggesting it as the most toxic among the tested chemicals. Diet supplements reduced toxicity of tested chemicals, especially when Spirulina and tamarind were given together.

Topics: Acid Phosphatase; Alkaline Phosphatase; Alum Compounds; Aluminum Compounds; Animal Feed; Animals; Antioxidants; Capsules; Cyprinodontiformes; Dietary Supplements; Drug Evaluation, Preclinical; Erythrocytes, Abnormal; Fluorides; Fruit; Kidney; Micronutrients; Phytotherapy; Plant Preparations; Proteins; Seasons; Sodium Fluoride; Spirulina; Suspensions; Tamarindus; Water Pollutants, Chemical

AphA is a magnesium-dependent, bacterial class B acid phosphatase that catalyzes the hydrolysis of a variety of phosphoester substrates and belongs to the DDDD superfamily of phosphohydrolases. The recently reported crystal structure of AphA from Escherichia coli has revealed the quaternary structure of the enzyme together with hints about its catalytic mechanism. The present work reports the crystal structures of AphA from E. coli in complex with substrate, transition-state, and intermediate analogues. The structures provide new insights into the mechanism of the enzyme and allow a revision of some aspects of the previously proposed mechanism that have broader implications for all the phosphatases of the DDDD superfamily.

Topics: Acid Phosphatase; Adenine; Aluminum Compounds; Aniline Compounds; Beryllium; Catalysis; Catalytic Domain; Crystallography, X-Ray; Enzyme Inhibitors; Escherichia coli; Escherichia coli Proteins; Fluorides; Hydrogen Bonding; Multigene Family; Organophosphonates; Organophosphorus Compounds; Protein Structure, Secondary; Substrate Specificity